Continuous closed wound suction units which are portable, will not collapse, and are made of a nonreactive material, are used to remove fluids from operative wounds. Many articles have documented the value of closed suction drainage since it was introduced in 1952. One excellent collective review about this subject is Moss, James P., Historical and Current Perspectives on Surgical Drainage, Surgery, Gynecology & Obstetrics, 1981; 152: 517-525. The suction catheters are left in place until they are no longer effective, then they are removed. However, the suction catheters may become occluded by tissue, clots, and necrotic material. Although the incidence of this obstruction is low in small wounds, every surgeon has had the experience of removing a suction catheter only to have a gush of serosanguinous fluid come out of the catheter site. A worse experience for the surgeon and patient is to first remove a suction catheter and then have a collection of fluid build up and form an abscess. Obviously, the suction catheter can become obstructed before the fluid in the operative site can be removed.
The mechanism of obstructin has been studied in, for example, Zacharski, Lee R., Mechanism of Obstruction of Closed-Wound Suction Tubing, Archives of Surgery, 1979; 144: 644-615. Dr. Zacharski and his associates tested suction catheters for occlusion after they were removed, then cut them into short segments and microscopically examined the contents. Although no occlusion was clinically evident in any one of the twenty-one suction catheters examined, all the tubes were plugged by clots and debris. Some were plugged throughout their entire length, and others showed segmental plugging. Only one out of twenty-one tubes examined was free of any plug. He also noted that solid contents (the plugs) were not adherent to the tube wall. The surprising finding was that organized clots with fibrin were relatively scarce. The plugs were debris and necrotic tissue from muscle, fat, and blood vessels. Accordingly, Dr. Zacharski concluded that meticulous wound flushing should be done at the end of every procedure. This advice was and is followed. Dr. Zacharski also suggested tubes of different designs. Silastic rigid tubes with multiple perforations are now commercially available and appear to work best. However, suction catheter drains still become occluded especially in the patients who have had the more extensive surgical procedures. These are the very patients who cannot afford to develop an occlusion, an abscess, or an infection
It is also well known that catheters or drains and the wound around them are a conduit for bacteria, and overwhelming evidence shows this to be a two way conduit. Therefore, surgeons cannot simply use more drains, larger drains, or squirt fluid through the drain back into the patient's wound to remove the debris and clots from a suction drainage catheter. One alternative is disclosed by Arthur J., in The Place of Wound Drainage in Surgery with Description of a New Drain, Archives of Surgery, 1960; 81: 870-873, which discloses use of a Foley catheter. A double lumen construction permits aspiration, irrigation with saline, or continuous drip with suction. Freund, H., Simple Method to Prolong and Improve the Function Hemovac Drains, American Journal of Surgery, 1975; 129: 600. discloses drainage tubes aspirated with a needle and syringe. Dr. Peter R. Jochinsen in Method to Prevent Suction Catheter Drainage Obstruction, Surgery, Gynecology, and Obstetrics, 1976; 142: 748-749, disclosed dividing the drainage tube at the time of surgery, interposing a soft rubber tube, and the stripping the collapsible rubber tube toward the suction catheter every day. Sondak, Vernon K., A Simple Inexpensive Technique for Clearing Obstructed Closed Suction Drainage Catheters, Surgery, Gynecology, and Obstetrics, 1985; 161: 595-596, discusses a "catheter thrombectomy. A Fogarty balloon tipped catheter uses a central venous catheter for the "catheter thrombectomy." Halejian, Barry Aud, Maintaining Chest Tube Patency, Surgery, Gynecology, and Obstetrics, 1987; 142: 521, discloses a respirator suction catheter for the same purpose. Finally Wackym, Phillip Ashley, A New Technique to Maintain Closed-Suction Drainage Catheter Function, Archives of Otolaryngology and Hand and Neck Surgery, 1987, 113: 57-58 discloses a pediatric feeding tube and syringe to clear the suction catheter. incidentally, the article discusses a catheter obstruction incidence of about 3%, but this percentage would vary with diameter of the drain, amount of suction, size of the wound, and a whole host of other variables.
Despite accepted recognition of the desirability of keeping a closed suction closed, the recommendations in the literature about methods to clear the suction catheter of clots and debris violate the closed system concept. Moreover, other systems, such as those disclosed in U.S. Pat. Nos. 3,958,573, 4,894,056, 3,863,641, 3,595,241, 396,754, 3,908,664 and 4,790,812 do not provide a closed sterile environment while still permitting easy clearing of drainage catheters.